1. Field of the Invention
This invention relates to a circuit characteristic adjusting method which is suitable for adjustment and selection of functions thereof.
2. Related Art
Heretofore, adjustment or selection of the electrical characteristic of a general electronic circuit element is carried out as follows: That is, element components, or suitable element components which can be estimated in an inspection step are mounted on an element component mounting section which is provided redundantly or preliminarily, to adjust the electrical characteristic of the circuit body. Alternatively, it is achieved by connecting wires such as jumper wires. That is, the circuit characteristic is adjusted by attaching element components or the like.
On the other hand, in an IC circuit body, as in the case of a memory or general purpose IC, a wiring pattern on the chip is directly cut, to disconnect a redundant element section or circuit section therefrom, to adjust the circuit characteristic.
In the selection of a function of the above-described general electronic circuit body, at the stage that the functional characteristic can be confirmed it is determined whether or not the functional characteristic is acceptable, and according to the result of determination its components are installed or removed or replaced for adjustment of the circuit characteristic. Hence, the above-described work is considerably intricate. Furthermore, since those components are generally individual (separate) components, it is necessary to provide a space large enough to install them.
On the other hand, a method of cutting a wiring pattern on the chip of an IC circuit for adjustment of the latter, suffers from the following difficulties: Even if the work is carried out after the components together with other components are installed on the substrate, it must be done before the IC circuit is sealed, and therefore the work is low in efficiency and the circuit body is low in protectiveness. In addition, part of the step of handling the IC circuit must be performed in the step of assembling the circuit body. Hence, it is difficult to set up a good circumferential condition for the work. Furthermore, foreign matter may contaminate the IC circuit, sticking to the latter, if there is a delicate element such as a crystal oscillator (described later) near it. That is, when the wiring pattern is cut, foreign matters scattered or remained may adversely affect the delicate element instantaneously or as the environmental condition changes